Holley 4224

I myself am no carb guru and haven't had any personal running/tuning experience with these carbs but I've done a lot of research on them and have compiled some info that might be helpful to others with questions. I wanted to bring a lot of that information as well as more in depth photos of the carb in pieces to one place to make it easier for the next person.


The Holley list #4224 is a unique model carburetor for it is the only or one of few 4160 models with mechanical 1:1 linkage. In 4160 fashion its fitted with a Primary metering block that comes with standard #76 main jets and a #12 Secondary metering plate equivalent to #73 jets.
It is fitted with one 50cc accelerator pump that feeds a .o25" center mounted discharge nozzle that supplies all 4 barrels. The base plate is made up of four 1-11/16" diameter throttle blades, the secondary throttle blades are offset on the shaft. The primary venturi is 1-1/4"diameter while the secondary is 1-5/16" diameter. To be continued..... it's late.



Many of the modifications done to these carburetors remain the same across the references attached so it's hard to argue with the reliability of the changes.

Paul Blevin 4224 Carb Setup


Holley Detailed Breakdown


Edelbrock Carburetor Setup On Tunnel Ram




Bill Jenkins 4224 Carb Setup

Originally Holley called them Centra-Flow but everyone called them Center Squirters and the name stock.

The 50 cc accel pump is called the REO pump

Trivia: where did that name come from??

Thanks
Randy

thank you for posting a rather informative bit of carb related info and related pictures!

http://garage.grumpysperformance.com/index.php?threads/holley-accelerator-pumps-cams.1790/

http://garage.grumpysperformance.com/index.php?threads/tuning-a-tunnel-ram-intake.5175/

http://garage.grumpysperformance.com/index.php?threads/setting-up-your-fuel-system.211/

http://garage.grumpysperformance.com/index.php?threads/carb-tuning-info-and-links.109/

http://garage.grumpysperformance.co...spacers-and-related-intake-modification.1038/

http://garage.grumpysperformance.com/index.php?threads/holley-annular-vs-down-leg-boosters.5229/

http://garage.grumpysperformance.co...-the-holley-4150-and-4160-series-carbs.10736/

http://garage.grumpysperformance.com/index.php?threads/how-do-i-know-the-power-valves-working.11157/

GLHS60 said:

Originally Holley called them Centra-Flow but everyone called them Center Squirters and the name stock.

The 50 cc accel pump is called the REO pump

Trivia: where did that name come from??

Thanks
Randy

Click to expand...

Thank you. Never knew about the Centra-Flow or at least I haven't found that info yet.

The REO pump wouldn't be any relation to Speedwagon would it?

Grumpy said:

thank you for posting a rather informative bit of carb related info and related pictures!

Click to expand...

Least I could do Grumpy. This makes it much easier for me to reference just one place for all the material as well as leaving it open for additions by others. I have plenty more to edit and add to this. I hope to provide a list a parts for modifying these carburetors as well as asking some questions to clear up a few ideas that I have.

Right, the REO 50 cc, per 10 strokes, pump was originally used on late 1950's REO trucks with a Holley 2 bbl.

Centra-Flow and 3 bbl ad from 1969. Both were great carbs!!

Thanks
Randy

for the young guys that might never see a holley three barrel carb

http://garage.grumpysperformance.com/index.php?threads/the-holley-three-barrel-carb.3037/

Its been years since I owned my 1963 Dodge but I never found a carb that out ran the old 3 bbl.

Some equaled it but none drove as good or ran faster.

No doubt there are better carbs now but I have fond memories!!

Thanks
Randy

yes , so do I!
I had a three barrel holley on my first 496 BBC when I broke it in initially

Here's a picture of the secondary side of the 4224 main body. The Blue dots indicate functioning orifices. The Red dots indicate the screw holes for the metering plate. The Yellow dots indicate dead ends, or locating holes. The lowest set of blue dots feed the transfer slots while the yellow dots next to them are dead ends but these could be drilled to from the bottom to open up the orifice for a 4 corner idle as well as drilling the appropriate hole on the bottom side of the throttle blades to interconnect with the passage in the throttle plate.

Here's some bolt on equipment for upgrading the 4224. (Please, those with the experience correct me if I'm wrong on any of this. A lot of this I've gathered from reading through other forums and I'm not 100% sure on some of it.)

A lot of this is in reference to sideways mounted carburetors. I will say that running the 4224's inline is recommended by Holley and makes it easier to setup the throttle linkage. This is an effective and simple way of running them other than making changes to the secondary sides of the carburetors requires you to remove one of them. I believe adding a secondary metering block limits the carburetors to being sideways mounted as the added length will cause interference between the two carbs.




Converting the fuel bowls from side hung to center hung.

It's an expensive modification if buying all new parts from Holley but like anything can be found cheaper "new or used" through other sources. Though the change is mostly about looks it can be helpful when mounting the carburetors sideways. The stock side hung bowls may have adverse effects during acceleration and deceleration that causes a lean or rich condition. (Any truth to this?) I've read when mounting the carburetors sideways that adding road race floats like the ones from Quick Fuel Part# 16-14 will help keep the float stabilized in the bowl as hard launches and braking occur. This is further supported by Quick Fuel's Drag Race Float Kit Part# 16-104 which would do both carburetors (2x4) without the hassle of selecting individual parts.

Don't let the price between the individual bowls and the kit fool you as from what I can see the individuals come bare. Buying them individually will kill any chance of doing this cheaply unless you already possess the parts to assemble them.

Remember the 4224 requires the 50cc accelerator pump as the 25cc pump doesn't provide enough fuel to support all 4 barrels opening at once.

Holley Fuel Bowl Conversion Kit Part# 34-2
https://www.holley.com/products/fue...ents/fuel_bowl_kits_and_components/parts/34-2

Holley Primary Fuel Bowl Part# 134-103
https://www.holley.com/products/fue...s/fuel_bowl_kits_and_components/parts/134-103


Holley Secondary Fuel Bowl Part# 134-102. Note: The 4224 secondary side DOES NOT have an accelerator pump so choose fuel bowls carefully when buying from other sources. It should be identified as "Fuel inlet only".
https://www.holley.com/products/fuel_systems/carburetor_components/fuel_bowl_kiwts_and_components/parts/134-102


Quick Fuel Road Race Float Part# 16-14
https://www.quickfueltechnology.com...owl-components/nitrophyl-float-road-race.html


Quick Fuel 2x4 Drag Race Float Kit Part# 16-104
https://www.quickfueltechnology.com...-bowl-components/2x4-drag-race-float-kit.html


There are several newer fuel bowls that can be used such as the quick change and aluminum bowls, just take your time and choose carefully.



Converting the secondary metering plate to a metering block.

Changing the secondary side to a metering block allows you to change the jetting. This proves to be cheaper than buying new plates to achieve the correct tune. The secondary side of the throttle plate and main body do not have the circuitry to support 4 corner idle adjustment. You can buy metering blocks with the idle adjust screws but the screws will not function as intended.

4224's do not have power valves so be sure to choose plates without this provision or plug the power valve hole if you plan to use this type of block.


Holley 4160 to 4150 conversion kit Part# 34-6. This kit is for converting the stock side hung fuel bowls.
https://www.holley.com/products/fue...nts/metering_block_conversion_kits/parts/34-6


Holley 4160 to 4150 conversion kit Part# 34-13. This kit is for use with center hung bowls if equipped.
https://www.holley.com/products/fue...ts/metering_block_conversion_kits/parts/34-13




Metering plate conversion.
If your not looking to change to a metering block you can use Quick Fuels metering plate conversion which allows you to install jets like a metering block.

Quick Fuel Part# 34-2. This kit is for stock side hung bowls.
https://www.quickfueltechnology.com...nents/side-pivot-float---billet-conv-kit.html


Quick Fuel Part#34-3. kjlThis kit is for center hung bowls.9
https://www.quickfueltechnology.com...llet-metering-plate-kit-vacuum-secondary.html

This is to fix all the quickfuel links.

Metering plate conversion.
If your not looking to change to a metering block you can use Quick Fuels metering plate conversion which allows you to install jets like a metering block. NOW SOLD UNDER HOLLEY.

Quick Fuel Part# 34-2. This kit is for stock side hung bowls.
https://www.holley.com/products/fue...uel_bowls_and_components/floats/parts/34-2QFT


Quick Fuel Part#34-3. This kit is for center hung bowls.
https://www.holley.com/products/fue.../metering_block_conversion_kits/parts/34-3QFT


Quick Fuel Road Race Float Part# 16-14
https://www.holley.com/products/fue...el_bowls_and_components/floats/parts/16-14QFT

Quick Fuel 2x4 Drag Race Float Kit Part# 16-104
https://www.holley.com/products/fue...l_bowls_and_components/floats/parts/16-104QFT

Holley 4224 rebuild kits.

Quickfuel Kit Part# 3-2003QFT
https://www.holley.com/products/fue...ponents/rebuild_kits/fast_kit/parts/3-2003QFT

Holley Renew Kit Part# 37-1537
https://www.holley.com/products/fue...mponents/rebuild_kits/renew_kit/parts/37-1537

Holley Trick Kit Part# 37-933
https://www.holley.com/products/fue...omponents/rebuild_kits/trick_kit/parts/37-933